The cobalt-60 incident in Delhi has thrown open many questions. Whether it was implementation of laws regarding the disposal of radioactive substances or the lack of knowledge among authorities dealing with such hazardous material, things have been found wanting. However, the most important was the question of attribution of the source of radioactive material- where the material came from? It took more than two weeks for Delhi police to come to a conclusion that the scraped gamma irradiator, the source of cobalt-60, came from DelhiUniversity. This investigation was handled completely by the Delhi police who went around the job without any technical inputs form the Atomic Energy Regulatory Board or the Department of Atomic Energy, following the lead of the source from one scrap dealer to another as is done in ordinary criminal cases.

A similar question of attribution of the radioactive or fissile material source underlies the case of nuclear terrorism. How can one determine the source of radioactive or fissile material if and when a terrorist incident of such nature takes place? Unlike conventional terrorist attacks, the use of nuclear material will bring in a completely different dynamics in to play. The fear and anger which it will generate can compel governments to take punitive actions against terrorist organizations they think are responsible and also, the states supporting them. Even if the situation is triggered by a non-state actor, it can easily snowball into a confrontation between states. Such a scenario in South Asia is not very hard to imagine. Determining the source of nuclear material therefore becomes extremely crucial. Nuclear Forensics seems to provide some answers to the dilemma of attribution.Nuclear material, both radioactive as well as fissile material, have a unique signature or fingerprint developed during the nuclear fuel cycle[1]. This signature or fingerprint depends upon the kind of radioisotopes present in the material, the isotopic composition and their mass ratio, age of the material (determined through its half-life), impurity content, kind of alloying (other metals) or cladding (metal with which the surface of the nuclear fuel is coated) and the presence of trace elements such as oxygen and strontium. These characteristics can define the origins and history of the material[2]. Some of these fingerprints can be present from the time of mining of the ore (kind of impurities) and others get induced while the material is enriched or processed. Most of the times, nuclear signatures can either lead to determination of the reactor type in which fuel is burnt/ irradiated or can provide vital clues about the geographic location where uranium ore is mined[3].In case of a nuclear detonation, the signature of the detonated material can be compared with a database of such nuclear signatures of other states to determine the source of nuclear material[4].The ability to attribute the source of nuclear material can act as a deterrent against those states who seek to deliberately shell out some material to the terrorists. It will also help in fomenting international legitimacy for punitive action against such terrorist organization as well as states that mentor them. However, negative attribution is equally important as is a case of positive attribution. In other words, determining non-involvement of certain states can prove equally helpful. Moreover, it will also augment the need for states to be more vigilant about safety and security of their nuclear material. Even if the material for detonation is stolen from premises of a state without its deliberate involvement, attribution will help in fixing liabilities for damage inflicted on the victim state. Since, it is a duty of individual states to protect their nuclear material, negligent states must be made to pay. However, technology has seldom been a replacement for political will. The most critical input needed in Nuclear Forensics is the availability of a database of nuclear signatures from all states having such capabilities. Though, IAEA, under the Comprehensive Safeguards Agreement, possesses a database for civilian nuclear fissile material, the real problem exists for weapon grade fissile material. Not many countries are willing to provide such critical information. For countries with advanced nuclear capabilities especially USA, sharing signatures may lead to proliferation since fledgling nuclear countries can improve their weapon designs with the help of such information. For Russia, on other hand, divulging such information may compromise its deterrent capabilities. The problem is more acute for countries with smaller nuclear forces like Pakistan. For them, because of their small inventory, maintaining ambiguity about nuclear capabilities is a part and parcel of their nuclear posturing. Moreover, sharing signatures may also divulge critical information about their nuclear histories, especially their proliferation record, which can be source of embarrassment. Maintenance of standard nuclear signatures is again a problem. States, bent on supporting clandestine nuclear activities and supporting terrorist, would like to alter the composition of their nuclear material to avoid detection. Many initiatives have been taken both multilaterally as well as by individual states to come to a solution for database and increase prospects of success for Nuclear Forensics. Nuclear Smuggling International Technical Working Group (ITWG) is one such multilateral effort in place since 1995. More than 45 nations have joined this effort. Under this project a number of national laboratories coordinate their efforts to develop the science of nuclear forensics.The JointResearchCenter at the Institute of Trans-uranium Elements (ITU), Germany of the European Commission is also actively involved in Nuclear Forensics and constitution of a database of nuclear signatures. ITU has collaborated with Bochvar Institute in Russia to establish a small database of nuclear signatures. This is important since Russia is a source of lots of loose fissile material. The first time the institute carried on analysis of seized nuclear material was in the year 1992 and successfully traced it to Russian type graphite moderated reactor (RBMK)[5].Moreover, the Department of Atomic Energy, USA has its own Spent Nuclear Fuel database of nuclear fuel produced in USA. France is also involved in compiling such data called the Spent Fuel Isotopic Composition Database (SFCOMPO). IAEA also maintains a small database from the information collected from the nuclear facilities safeguarded by it. Conclusion

Successful attribution will be very crucial in post-detonation international environment. If the post 9/11 world is an example, the picture of international politics after a successful nuclear terrorist attack is not very hard to conceptualize. Moreover, equally important is the issue in context of South Asia. The rousing public passions on terrorist attacks have indicated the kind of unrest in the society. What is also to be witnessed is the frustration which follows the rounds of accusations and counter-accusations between India and Pakistan over the responsibility of terrorist attacks?Successful Nuclear Forensics will provide a firm base on which claims of liability and responsibility can be made. Moreover, it can also provide sound justification for retaliation. However, most important is the fear of retribution which any successful attribution of source of the nuclear material can bring into play. Deterrence by attribution can well be an asset in case of nuclear security.

* Author is Research Officer in the Institute of Peace and Conflict Studies, New Delhi

[1]The Nuclear Fuel Cycle involves mining of Uranium ore, milling and processing it to chemical compounds like Uranium Hexafluoride (UF6) or Uranium Oxide (UO2). It is enriched to increase the content of the radioactive isotope of Uranium called U235 which can then be used in weapons or for energy production in nuclear reactors. This is generally known as the front side of the NFC. When Uranium is burned or irradiated in nuclear reactors, it produces plutonium. However, plutonium in this stage exists with many other very radioactive elements called actinides and has to be reprocessed for use in weapons. This is called the back side of the NFC. http://www.world-nuclear.org/info/inf03.html

[2] For example, the concentration of various isotopes of Uranium like U235, U234 and U238 can reveal information regarding the geographical location from where uranium ore is mined since concentration of these isotopes changes from place to place. Similarly presence of artificial isotopes such as U232 and U234 indicate that uranium has already been irradiated in the reactor. In case of plutonium, the concentration of Pl242 and Pl240 is an indicator of the reactor type in which uranium has initially been burned to produce plutonium.

[4] “Nuclear Forensics : Role, State of the Art, Program Needs”, Report of the Joint Working Group of the American Physical Society and the American Association for the Advancement of Sciences, available at cstsp.aaas.org/files/Complete.pdf( accessed on 20June 2010)